Conventionally, apparatuses such as Doppler radars, wind profilers, Doppler lidars, and Doppler sodars are used as apparatuses to measure wind at remote locations in the atmosphere. These apparatuses radiate electromagnetic waves or sound waves into space, receive reflection by precipitation particles, atmospheric turbulence, aerosol, etc., and calculate the wind direction and wind speed of winds in the atmosphere from Doppler frequency shifts of the received signals.
Hereinafter, a Doppler lidar is described as an example of a wind measuring apparatus. What is measured directly by a Doppler lidar is a line-of-sight direction component (hereinafter referred to as “LOS speed”), which is a projection onto a direction of a beam of the velocity of aerosol or the like blown by the wind in the atmosphere and thus traveling at the same velocity as that of the wind. By measuring LOS speeds in three or more directions different from each other, and by using the LOS speeds and performing operation such as the velocity azimuth display (VAD) method, which is described in Non-Patent Literature 1, or the three beam method, the four beam method, or the five beam method, which are described in Non-Patent Literature 2, the wind direction and wind speed are calculated.
Such wind measuring apparatuses include those mounted on a traveling platform such as a ship or an aircraft in addition to those fixed on the ground. Other than spontaneous traveling, such a traveling platform generally makes movement affected by the external environment such as winds and waves, that is, motion. For this reason, for example as illustrated in Patent Literature 1 and Patent Literature 2, a motion sensor is added, and by using motion information obtained therefrom, that is, attitude angles (motion angle) such as a roll angle, a pitch angle, and a yaw angle, or an attitude angular velocity and information about an angular acceleration, movement of a platform is controlled such that motion to be received by the platform is canceled, and/or correction taking account of an amount of rotation or movement (translation) due to the motion of the platform is performed on the wind direction and wind speed calculated from measured data containing an influence of the motion.